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Discussion Starter · #43 ·
I have had all three A45's.
First Gen 80K Km's
FL 40 K Km's
Current car, built October 19, only 8K KMs, ( in the world's strictest COVID restrictions) on it since it was delivered April 2020.
Yes I know seven months old before I saw it.
Highly frustrating at the time; however, not unusual when one is on the other side of the world.
If I was to list the excuses from MB Australia, it would take a seriously long (and boring) post.
 

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Once you guys get vaxed up you'll be cruising and adding the miles. At least its winter there currently so less of an issue for being in lockdown.
 

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He handbuilt the Saab 90 Turbo in Sweden in 1971, seven years before its release didn't you know? ;)
And still upgraded turbo for an additional 5 hp.

Please do me a favour and have another look at the numbers posted on the original thread from the Australian Maha.
Apart from the supposed "stock" number, on which you have commented previously, please just look at the other numbers and tell me if anything jumps out at you, particularly in light of the Maha operational thread which you so kindly reposted.

With the W177 A45S,. could a Tuner run beyond the turbo Choke Flow number and into overspeed, with no other mods?
Easily.
You and I can debate whether this is going to occur at 465 HP, 475 HP 485 HP or 495HP. Maha HP, however, at some point it will happen.
What is the most likely reason for this NOT happening?
A good Tuner is going to get to some combination of variables where he cannot make any more power, (Choke Flow) and IF he really IS any good, back the variables off slightly.
Thus deliberately, or simply by dint of good Tuning practice, save the turbo.

As for where one goes beyond that point, that is where it gets REALLY interesting.
Now, remember our Australian cars have no filter and the AMG performance exhaust as standard.
Also, I would guess by your posts that you would have already had a really good look at the air intake system into the compressor?
Do you really believe this can be significantly improved, at least in the context of the stock Turbo's Choke Flow?
I certainly don't.

What i am really saying is, I don't see a "Stage 2". Perhaps there is in the UK, with an "export" exhaust system; however not for us, as we are effectively already there.
Have you seen what Akrapovic claims for their 200 CPI downpipe over stock? 6 HP at peak RPM!!! :), which is obviously somewhere between absurd and pointless.
All this on the stock Turbo, of course.

Which brings us right back to the beginning.
My original point being, if one is going to want to go beyond what you (and the Tuning Industry) describe as "Stage 1", it is going to take a larger compressor wheel turbo.
Why don't you tell me what you find strange.

Well gpf cars should be able to make more than 6 hp once that thing gets out of the way. Not saying it's gonna be anything like S3 8p, MK6 Golf R, Edition 30 GTI etc whopping exhaust gains. BYD engine in specific (found in Edition 30 GTI / Pirelli Edition in Australia), 230 hp stock but every single one of them dynoed at no less than 240, made 310-320 at 100oct RON setting which may seem impressive for just a tune, but as it was a detuned version of S3 8p (265 hp stock) it was pretty much expected. What was truly impressive though, was the exhaust gains (plus hpfp and ic) to 370 hp. That's 50-60 hp gains from stage 1 to stage 2+ (there was also a stage 2 that involved keeping the stock hpfp but nobody kept it stock - you often had to upgrade anyway as it was already worn and not able to keep up with 135bar iirc). Nowadays hot hatches come off the factory with plenty of upgrades already, so you don't have to go far, like you said, you're already there. MQB gen for instance. MK3 Seat Leon Cupra (gpf version, 290 stock), makes 370 hp with just a tune at 100oct RON. Stage 2 does not involve an exhaust, just an intake, ic and a small tweak in the tune and you can make as much as 400 hp at 100oct RON. So we're talking stage 1 to 2 +30 hp as opposed to 60 of those older hot hatches. So it's obvious newer cars come off the factory at a significantly better state, where almost all additional power comes right off the bat with a tune.

Same thing with the A45s. Almost all power should come with the tune, however, I believe Euro spec A45s should make at least +20 hp with a 200 cell gpf-delete cat. There's no way that thing is only 6 hp restrictive.

As for the intake. I don't think intakes make much of a difference, but they do make some difference, in certain applications. Some tuners even require them, such as the case of the Seat Leon Cupra 290. And it's not a marketing thing, as you can get any intake you want, you don't have to buy their in house product. So it does something. In the context of the stock Turbo's Choke Flow I dunno, but mass flow definitely.
 

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Discussion Starter · #46 ·
And still upgraded turbo for an additional 5 hp.


Why don't you tell me what you find strange.

Well gpf cars should be able to make more than 6 hp once that thing gets out of the way. Not saying it's gonna be anything like S3 8p, MK6 Golf R, Edition 30 GTI etc whopping exhaust gains. BYD engine in specific (found in Edition 30 GTI / Pirelli Edition in Australia), 230 hp stock but every single one of them dynoed at no less than 240, made 310-320 at 100oct RON setting which may seem impressive for just a tune, but as it was a detuned version of S3 8p (265 hp stock) it was pretty much expected. What was truly impressive though, was the exhaust gains (plus hpfp and ic) to 370 hp. That's 50-60 hp gains from stage 1 to stage 2+ (there was also a stage 2 that involved keeping the stock hpfp but nobody kept it stock - you often had to upgrade anyway as it was already worn and not able to keep up with 135bar iirc). Nowadays hot hatches come off the factory with plenty of upgrades already, so you don't have to go far, like you said, you're already there. MQB gen for instance. MK3 Seat Leon Cupra (gpf version, 290 stock), makes 370 hp with just a tune at 100oct RON. Stage 2 does not involve an exhaust, just an intake, ic and a small tweak in the tune and you can make as much as 400 hp at 100oct RON. So we're talking stage 1 to 2 +30 hp as opposed to 60 of those older hot hatches. So it's obvious newer cars come off the factory at a significantly better state, where almost all additional power comes right off the bat with a tune.

Same thing with the A45s. Almost all power should come with the tune, however, I believe Euro spec A45s should make at least +20 hp with a 200 cell gpf-delete cat. There's no way that thing is only 6 hp restrictive.

As for the intake. I don't think intakes make much of a difference, but they do make some difference, in certain applications. Some tuners even require them, such as the case of the Seat Leon Cupra 290. And it's not a marketing thing, as you can get any intake you want, you don't have to buy their in house product. So it does something. In the context of the stock Turbo's Choke Flow I dunno, but mass flow definitely.
I was not generalising in the way you have here.
ALL my comments, from the first post, were ONLY in the context of the W177 A45S, absolutely no other vehicle, if for no other reason than I don't have hard Engineering data on the turbos of most of the vehicles you list.

GPF Delete on the W177 A45S?
You may well be correct.
Akrapovic are only comparing Cat with Cat, which is the correct engineering approach as the GPF is a seperate component.
My point being, the stock Cat is quite low restriction, in its own right.
 

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How come MB isn't providing more headroom for peace of mind? Don't you wonder? Why do you think Audi provides 30%? Could there be any reason other than making sure it's gonna stay out of problems for at least 100k miles, no matter your driving style and whether you are in the Arizona desert or northern Canada? 10% headroom is like, extremely close to the design limits. Wouldn't it affect lifespan?
 
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Discussion Starter · #48 ·
How come MB isn't providing more headroom for peace of mind? Don't you wonder? Why do you think Audi provides 30%? Could there be any reason other than making sure it's gonna stay out of problems for at least 100k miles, no matter your driving style and whether you are in the Arizona desert or northern Canada? 10% headroom is like, extremely close to the design limits. Wouldn't it affect lifespan?
Ah Ha!!!
NOW you are asking the correct questions!!
I most certainly DO wonder.
I just wish I had had the turbo maps when I did my factory visit in May of 2019, the very week in fact in which they started the M139 going down the world's most seriously impressive, (even more than the V8 downstairs) engine assembly line.
As I said in a previous post, the On Line videos don't begin to do it justice.
Unfortunately, I only received the maps some months later and as they say, with AMG, "no correspondence will be entered into" !!

I could GUESS, (simply based on how Engineers would think) though.
As you already know, the engine has, until Ferrari's most recent release, the world's highest specific output of any production engine.
Based on this, I believe AMG would seriously prefer that NONE of us increased that output.
So, easy way to control the typical Tuning industry?
Turbo Mass Flow choke.
Their engine management is State of the Art and they obviously feel it is sufficiently sophisticated to be able to cope with the type of extremes which you describe.
Although, that said, have you noticed, the 'S's are on restricted market release?
EG The States don't get them, in any body style?
Also, how familiar are you with the S's overall cooling system?
 

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And so they used a relatively small turbo. Is it smaller than RS3's then?

Yes I've read about how extremely sophisticated MG1 is.

I know the turbo is air, oil and water cooled at the same time. I know rotating the engine resulted in better cooling too. And I know it's got a 2 stage ic (?) if I'm not mistaken. You're saying its sophisticated cooling system is able to ensure a lifespan that is on par with let's say a 30% headroom?

And would that mean RS3 isn't equipped with such systems, so Audi gave it a bigger headroom to compensate?
 

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Oh missed that. Yes, unfortunately the States don't get plenty of the higher spec Euro versions anyway, so it didn't surprise me. Every single one of my car enthusiast friends complain about that.
 

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Discussion Starter · #51 ·
And so they used a relatively small turbo. Is it smaller than RS3's then?

Yes I've read about how extremely sophisticated MG1 is.

I know the turbo is air, oil and water cooled at the same time. I know rotating the engine resulted in better cooling too. And I know it's got a 2 stage ic (?) if I'm not mistaken. You're saying its sophisticated cooling system is able to ensure a lifespan that is on par with let's say a 30% headroom?

And would that mean RS3 isn't equipped with such systems, so Audi gave it a bigger headroom to compensate?
!) 20% smaller, cold and hot end than the RS3

2) I was actually referring to the engine itself.
2.1) The engine is effectively "dry decked".
Meaning almost no holes in the block deck surface on which the head is mounted.
Common in Motorsport, almost unheard of in Production.
Benefit? Much more reliable combustion chamber sealing
2.2) The engine has two, essentially separate, water cooling systems.
Two completely seperate radiators, stacked one in front of the other.
One radiator is used for the cylinder head alone, with mechanically driven water pump/ thermostat. (reasonably conventional).
The second radiator is used for the cylinder block alone, with an electrically driven water pump, controlled by the ECU.
Benefit: You can run the cylinder head much cooler than the block. There are all sorts of Engineering implications resulting from this, which would be a post in themselves.
2.3) The intercooler circuit has a very large,(almost the same frontal area as of the two water radiators) , intercooler water heat exchanger in front of the radiators.
If you look in your Grille, this is predominantly at what you are looking.
I say "predominantly", since if you look at the lower 20% of the grill opening, you are actually looking at one, of two, A/C condensers.
So, this is located below the Intercooler heat exchanger, in the same vertical plane.
The second A/C condenser is located under the RHS headlight.
Why so much A/C condenser?
Because under the LHS headlight, along with the water pump for the Intercooler circuit and the control valve for the trans oil cooler, is ANOTHER heat exchanger!!
This one between the cooling water of the intercooler circuit and the A/C system.
Which, of course, increases the heat load on the A/C system. hence the two a/c condensers.
Now, I could keep going on; however jus let me say, the difference in level of technical sophistication between the W177 A45S and the current RS3 is genuinely night and day.
Remember, because of all the VW Group issues, the current RS3 is actually one full generation behind the current A45S.
You could, of course, have an entirely different discussion about whether all this technical sophistication is a good or bad thing.

I have recently had the nose cone off my car and as my Body guy said with real conviction, our cars are the perfect justification for very comprehensive insurance!! :)

I hate to think what a serious front end would cost to repair on our cars!! :)

So a comparison between the two vehicles is really not apples with apples, at least from an Engineering perspective,
 

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Discussion Starter · #52 ·
And so they used a relatively small turbo. Is it smaller than RS3's then?

Yes I've read about how extremely sophisticated MG1 is.

I know the turbo is air, oil and water cooled at the same time. I know rotating the engine resulted in better cooling too. And I know it's got a 2 stage ic (?) if I'm not mistaken. You're saying its sophisticated cooling system is able to ensure a lifespan that is on par with let's say a 30% headroom?

And would that mean RS3 isn't equipped with such systems, so Audi gave it a bigger headroom to compensate?

My fast answer on the RS3, does not clearly describe the differences between the two turbos/ applications.

The RS3 not only has at least 20% more maximum mass flow available from its turbo, it is also operating at a significantly lower pressure ratio as supplied by Audi.
This is important, since the choke flow curve is exactly that, a curve.
In other words, there is more mass flow available at at a 2.5:1 P/R than at the 3.1 P/R at which our turbo is working.
This provides the Audi Tuner with LOTS more flexibility than our car provides.
As I said previously, I suspect from AMG's perspective, quite deliberately.
 

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Thanks for the additional engine info. I've read our engines are closed deck.

Well I believe no car maker would recommend output increase but why would AMG be so passionately against it?

I wanna get back to the turbo debate. Well, I'm a Garrett fan ok? Particularly GTX Gen II series that's been out for a few years. I've also begun to appreciate the tech behind G series, which is their latest development, just don't have a lot of feedback. They seem to make similar power to GTX Gen II series even though they are even smaller frame. So anyway, let me post the turbo specs of GTX 2860R Gen II and GTX 2867R Gen II.

GTX 2860R Gen II
Compressor Inducer 46 mm
Exducer 60 mm
Trim 58
A/R 0.60
Turbine Inducer 54 mm
Exducer 47 mm
Trim 76

GTX 2867R Gen II
Compressor Inducer 50 mm
Exducer 67 mm
Trim 55
A/R 0.60
Turbine Inducer 54 mm
Exducer 47 mm
Trim 76

M139 turbo (copied from your post)
Compressor Inducer 50 mm
Exducer 63 mm
Turbine Inducer 57 mm
Exducer 50 mm

On their official site, Garrett claims 475 hp for GTX 2860R Gen II and 550 hp for GTX 2867R Gen II. However if you look at their compressor map, it looks like they make up to 425 and 500 hp respectively. Why would they claim 50 hp above the compressor map? You see where I'm getting at.

Furthermore, as you can see, our turbo is bigger than GTX 2860R Gen II. And one could go about differences in technology, how new developments increase efficiency, but isn't our turbo new? I thought it was developed specifically for the M139. So that would make it a few years newer than the Garrett one. And yet you're saying it can make up to 465 hp. Looking at all the above, I would think our turbo can reasonably make 515 hp, which is about the highest I've seen tuners advertize, although most are in the area of sub 500, which, if anything, seems to me is rather safe too. I'd like your input.

Here's the Garrett links for further reading (including compressor maps):

 

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Discussion Starter · #54 ·
Thanks for the additional engine info. I've read our engines are closed deck.

Well I believe no car maker would recommend output increase but why would AMG be so passionately against it?

I wanna get back to the turbo debate. Well, I'm a Garrett fan ok? Particularly GTX Gen II series that's been out for a few years. I've also begun to appreciate the tech behind G series, which is their latest development, just don't have a lot of feedback. They seem to make similar power to GTX Gen II series even though they are even smaller frame. So anyway, let me post the turbo specs of GTX 2860R Gen II and GTX 2867R Gen II.

GTX 2860R Gen II
Compressor Inducer 46 mm
Exducer 60 mm
Trim 58
A/R 0.60
Turbine Inducer 54 mm
Exducer 47 mm
Trim 76

GTX 2867R Gen II
Compressor Inducer 50 mm
Exducer 67 mm
Trim 55
A/R 0.60
Turbine Inducer 54 mm
Exducer 47 mm
Trim 76

M139 turbo (copied from your post)
Compressor Inducer 50 mm
Exducer 63 mm
Turbine Inducer 57 mm
Exducer 50 mm

On their official site, Garrett claims 475 hp for GTX 2860R Gen II and 550 hp for GTX 2867R Gen II. However if you look at their compressor map, it looks like they make up to 425 and 500 hp respectively. Why would they claim 50 hp above the compressor map? You see where I'm getting at.

Furthermore, as you can see, our turbo is bigger than GTX 2860R Gen II. And one could go about differences in technology, how new developments increase efficiency, but isn't our turbo new? I thought it was developed specifically for the M139. So that would make it a few years newer than the Garrett one. And yet you're saying it can make up to 465 hp. Looking at all the above, I would think our turbo can reasonably make 515 hp, which is about the highest I've seen tuners advertize, although most are in the area of sub 500, which, if anything, seems to me is rather safe too. I'd like your input.

Here's the Garrett links for further reading (including compressor maps):

Back in the post where I provided the Inducer /. Exducer numbers, if you look again, I cautioned you against using these dimensions as an arbiter and / or for comparison purposes.
It is one of the reasons I was initially reluctant to supply them.
In fact, what you have done is precisely what I feared.
You obviously dismissed my start / end career example ! :)

You can ONLY do what you have done, IE use these dimensions for comparison purposes, when the wheel technology, (either compressor or turbine) is identical.

I do mean, identical. EG, do you see the example that Garrett provides for the difference in flow between dimensionally identical Gen 1 and Gen 2?
That, is precisely the point. Change the wheel tech and any purely dimensional comparison becomes meaningless.

Do you remember when I posted that the compressor wheel tech in our M139 turbo is only average?
I was serious, it is pretty much middle of the road for BW / KKK's current Production turbos.
Actually, as is the entire turbo, except for couple of interesting high temp durability features.
Really, nothing special and certainly no where near the performance / physical envelope of Garrett Motorsport turbos such as the Gen 2 and even more so, the G Series.
Yes, I am also a Garrett advocate, although I suspect for stronger reasons than your own, with all due respect.

Finally, the HP claims from the Marketing Dept. of Garrett vis-à-vis the two models you quoted.

Don't' forget, these ARE Motorsport turbos, with Forged, Milled compressor wheels, far better equipped than your average production turbo to handle overspeed.
The fact that the 2860 would be deep into the 50/55% flow line at 3:! P/R and probably running at 200K RPM or thereabouts, at 475 HP, simply makes it a foolish choice.
NO professional Engineer would make that choice, simply because there are far better options available for that power level.
Who would chose 50 to 75C higher compressor discharge temps, when one didn't have to?
Not to mention, higher turbine back pressure numbers?
Would the 2860 live, under those circumstances where a regular production unit would not?
Almost certainly; however, don't forget, the end of line production cost of that 2860 Gen 2 is probably somewhere approaching five times of the BW/KKK on our M139.

The 2867 is not as an extreme example as the 2860; however the general comments still apply.
There are far better 550 HP turbos available in the Garrett Motorsport range.

You do realise, I hope, that the point of a compressor map is to match the turbo to get the engine flow requirements running up the dotted line in the middle of the map?
NOT operating in the top right corner, or indeed OFF it, which is well and truly where a 500 HP Flywheel version of our stock M139 turbo would be operating.
 

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Back in the post where I provided the Inducer /. Exducer numbers, if you look again, I cautioned you against using these dimensions as an arbiter and / or for comparison purposes.
It is one of the reasons I was initially reluctant to supply them.
In fact, what you have done is precisely what I feared.
You obviously dismissed my start / end career example ! :)

You can ONLY do what you have done, IE use these dimensions for comparison purposes, when the wheel technology, (either compressor or turbine) is identical.

I do mean, identical. EG, do you see the example that Garrett provides for the difference in flow between dimensionally identical Gen 1 and Gen 2?
That, is precisely the point. Change the wheel tech and any purely dimensional comparison becomes meaningless.

Do you remember when I posted that the compressor wheel tech in our M139 turbo is only average?
I was serious, it is pretty much middle of the road for BW / KKK's current Production turbos.
Actually, as is the entire turbo, except for couple of interesting high temp durability features.
Really, nothing special and certainly no where near the performance / physical envelope of Garrett Motorsport turbos such as the Gen 2 and even more so, the G Series.
Yes, I am also a Garrett advocate, although I suspect for stronger reasons than your own, with all due respect.

Finally, the HP claims from the Marketing Dept. of Garrett vis-à-vis the two models you quoted.

Don't' forget, these ARE Motorsport turbos, with Forged, Milled compressor wheels, far better equipped than your average production turbo to handle overspeed.
The fact that the 2860 would be deep into the 50/55% flow line at 3:! P/R and probably running at 200K RPM or thereabouts, at 475 HP, simply makes it a foolish choice.
NO professional Engineer would make that choice, simply because there are far better options available for that power level.
Who would chose 50 to 75C higher compressor discharge temps, when one didn't have to?
Not to mention, higher turbine back pressure numbers?
Would the 2860 live, under those circumstances where a regular production unit would not?
Almost certainly; however, don't forget, the end of line production cost of that 2860 Gen 2 is probably somewhere approaching five times of the BW/KKK on our M139.

The 2867 is not as an extreme example as the 2860; however the general comments still apply.
There are far better 550 HP turbos available in the Garrett Motorsport range.

You do realise, I hope, that the point of a compressor map is to match the turbo to get the engine flow requirements running up the dotted line in the middle of the map?
NOT operating in the top right corner, or indeed OFF it, which is well and truly where a 500 HP Flywheel version of our stock M139 turbo would be operating.
"what you have done is precisely what I feared"
But I didn't. I did factor in the difference technology can make. I said that at the beginning of my last paragraph. I just imagined that our turbo was state of the art too, aside from the engine and the ECU. I also thought it was designed by BW specifically for our engine, so that would make it newer than any GTX Gen II series, or even G series for that matter. And since tech only moves forward, I would think it'd be at least as efficient, if not more, than GTX Gen II series. I know it uses roller bearings for instance, and it's a twin scroll. And that it's air, water and oil cooled. That's all I know about our turbo, and now I got the specs thanks to you. I'm not in the business like yourself, but I like searching, digging out info, even on things I'm probably never gonna put to use. Not gonna bother with upgrading the turbo for instance, as I got other plans. But I didn't do what you feared. I thought our turbo was technologically, at least on par with GTX Gen II.

Yes I saw Garrett's example that shows the difference between Gen I and II. Though I already knew Gen II was immensely better.

So what would be a good replacement turbo?
Just out of curiocity, I was gonna ask him the same thing. Though as I'm sure he'll say, there's no simple answer, as it highly depends on your target. Like what hp you are aiming at, how much lag you are willing to accept, how you are gonna drive your car. As a Garrett fan, I would think a good size turbo for our cars would be a 3071 Gen II or G25-660. Just don't have a lot of feedback on the G series, so I'd probably go with the Gen II. Maybe a 3076 Gen II for an extra 50-75 hp. And I would aim somewhere between 550 and 650 hp, just so I wouldn't have to max it out to get that power.

And with that said, @Turbo Ed remember I did admit a few posts back, that going bigger turbo is always the better solution, as opposed to maxing out our turbo. I only said there are ways to do so, such as running w/m. As I've already said I've been there and never had a problem, although I admit I didn't keep that setup long (as nearly everyone, just couldn't stay there). Which is one of the reasons I'm not gonna bother with further tuning this car other than getting a Brabus tune (and maybe a catback just for the sound), as I intend to keep it for several years if it proves to be reliable. In fact I could keep it over a decade. So this time around I need something mild, and super safe (and with a warranty).
 

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To me a good option would be plus 30-40% power with smilar spool to stock. So tech as much as frame size. Not sure such a turbo exists. Direct bolt on replacement would be ideal.
BW EFR series ang G series are about AUS$3-4k, compared to $10k for an Akraovic exhaust!
Assuming engine internals can handle extra power, fueling can keep up etc.
Would go E85.

Wishful thinking on my part, but i have gone >100% power increase in other cars with turbo upgrade and supporting mods. I uess in this segment the RS3 is a better starting point for mods.
 

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Discussion Starter · #58 ·
"what you have done is precisely what I feared"
But I didn't. I did factor in the difference technology can make. I said that at the beginning of my last paragraph. I just imagined that our turbo was state of the art too, aside from the engine and the ECU. I also thought it was designed by BW specifically for our engine, so that would make it newer than any GTX Gen II series, or even G series for that matter. And since tech only moves forward, I would think it'd be at least as efficient, if not more, than GTX Gen II series. I know it uses roller bearings for instance, and it's a twin scroll. And that it's air, water and oil cooled. That's all I know about our turbo, and now I got the specs thanks to you. I'm not in the business like yourself, but I like searching, digging out info, even on things I'm probably never gonna put to use. Not gonna bother with upgrading the turbo for instance, as I got other plans. But I didn't do what you feared. I thought our turbo was technologically, at least on par with GTX Gen II.

Yes I saw Garrett's example that shows the difference between Gen I and II. Though I already knew Gen II was immensely better.


Just out of curiosity, I was gonna ask him the same thing. Though as I'm sure he'll say, there's no simple answer, as it highly depends on your target. Like what HP you are aiming at, how much lag you are willing to accept, how you are gonna drive your car. As a Garrett fan, I would think a good size turbo for our cars would be a 3071 Gen II or G25-660. Just don't have a lot of feedback on the G series, so I'd probably go with the Gen II. Maybe a 3076 Gen II for an extra 50-75 hp. And I would aim somewhere between 550 and 650 HP, just so I wouldn't have to max it out to get that power.

And with that said, @Turbo Ed remember I did admit a few posts back, that going bigger turbo is always the better solution, as opposed to maxing out our turbo. I only said there are ways to do so, such as running w/m. As I've already said I've been there and never had a problem, although I admit I didn't keep that setup long (as nearly everyone, just couldn't stay there). Which is one of the reasons I'm not gonna bother with further tuning this car other than getting a Brabus tune (and maybe a Cat back just for the sound), as I intend to keep it for several years if it proves to be reliable. In fact I could keep it over a decade. So this time around I need something mild, and super safe (and with a warranty).
Ah, Theo, how well you have got to know me in such a short time!!!! :)
Most of the above is correct as written, so I shall leave it alone, except for adding a few things.
Garrett's aftermarket Motorsport turbos have been ball (not roller, that is simply a common journalistic error) bearing with split pulse (divided) optional turbine housings since the late '90's.
Technology advances in the Turbo industry, just as with the Automotive industry generally , does not move forward on an equal footing between various corporations.
That is why it is called, competition.
Which is a long winded way of saying, Garrett is in front of BW/KKK, at least from a technology perspective.
There are MANY criteria used when a car company decides on sourcing any component from any Tier 1 Supplier and technology is only one.
Although Garrett's absolute state of the art electric assisted turbo seems to have won them the fitment on the next Gen of our M139.

I'll just leave by reiterating my most important comment.
You cannot compare compressor flow (or turbine for that matter) by Inducer/ Exducer dimensions, unless the wheel tech is IDENTICAL.

Now I'll have a crack at Sixman's post!!
 

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Discussion Starter · #59 ·
To me a good option would be plus 30-40% power with similar spool to stock. So tech as much as frame size. Not sure such a turbo exists. Direct bolt on replacement would be ideal.
BW EFR series ang G series are about AUS$3-4k, compared to $10k for an Akrapovic exhaust!
Assuming engine internals can handle extra power, fuelling can keep up etc.
Would go E85.

Wishful thinking on my part, but i have gone >100% power increase in other cars with turbo upgrade and supporting mods. I guess in this segment the RS3 is a better starting point for mods.
Starting with your last comment, first, yes if you are looking to significantly mod the vehicle from stock, the RS3 is a "better", (read "easier) starting point.
Personally, before I purchased each of the three generations of A45 I have owned over the past six years, I drove the competition from Audi and BMW.
I came awful close to a M2-C.
However there are good reasons I I kept coming back to the A45. If you know Melbourne weather, you will understand.

Theo has outlined the issue quite well, so I shall not repeat him.

The end housings of our turbo are completely unique so, in all probability, there will not be a "bolt on" complete turbo for years.
(It took around 5 years for a "bolt-on" to be released for the M133 engine)
So, the only way to create a "bolt-on" in the short term is:-
1) Install a new, larger comp. wheel and re-machine the stock compressor housing to suit. (Currently, I think only Gottuned out of Poland has this option, although I believe TTE's out of Germany is close).
Gottuned's is good for around 550 HP Flywheel, and if TTE's previous offering for the M133 engine is anything to go by, it will be similar.
2) Install a complete new Core (rotating group), into re-machined turbine and compressor end housings. This is significantly more work than (1); however potentially a far better result.

Almost a "bolt-on" would be adaptors between the stock exhaust manifold and a complete turbo, such as suggested by Theo.

However, NONE of the above really answers your original question and the answer is at the moment, I don't' know.

I can tell you what NOT to use, if you want to go beyond 10-15% on the M139, which is the stock turbo.

I can also tell you what I shall be measuring before I make my final decision.

Even after that, my answer will almost certainly be two different turbos, based on under and over 550 HP, as a result of my previous comments regarding stock Connecting Rods

Anyway, here is the list of where I shall be measuring both temperature and pressure, before deciding on where to go with the turbo. (Not to mention, am I prepared to pull the engine for a Con Rod swap?)
HOT SIDE

1) at least two exhaust ports.
2) both turbine inlet passages
3) Cat inlet (also wideband O2)
4) Cat outlet (also wideband O2)
COLDSIDE
1) air cleaner outlet
2) compressor inlet
3) compressor outlet
4) Inlet manifold
5) Intercooler water In/ Out

I trust the preceding is of interest,
 

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Yeah, intetested to see what you find. The cost/performance improvement of current tunes and mods has me scratching my head a bit.
Aus delivered cars dont have the particulate filter, are there other differences as well in the exhaust system?. With the exhaust button on I find my A45s loud enough.
 
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